Rough Estimate
 

So here's the deal. My sister is studying abroad in Newcastle, England. I plan on visiting her on December 15 through January 11. We are not only planning to stay in Newcastle, but instead travel all round for the month I am there. Here's our tentitive plans: December 15-21 Newcastle, have place to stay for free.
December 21-26 Munich, Germany. Have to pay for airfare but have place to stay.
December 26-30 Italy. Must pay for transportation and places to stay.
December 31-January 3 London. Must pay for transportation and place to stay.
January 3-6 Ireland. Pay for trans and stay.
Jan 7 back to Newcastle for Newcastle VS. Liverpool game.
Jan. 7-10 Scotland. Pay for trans and stay.
Now my question is, and I know it might be hard to defer from the above information, how much money will I need to take? I was thinking a couple thousand. Too much? Too little? What is the cheapest way to get from England to Germany? Italy to England? If planes, will they be running a day before New Years Eve?
If anyone has done something remotely similar to my plans or knows anything about doing a lot of traveling on a tight budget, please give some advice! Thanks!

If you are suggesting that you take a couple thousand with you, don't. The ATM for cash and charging major purchases gives you a better exchange and less chance of losing all of your money by accident or theft. Of course, it might be more difficult to stay within budget that way.

You don't say where you are from so I am assuming the US.

There are a lot of budget airlines in Europe, often flying from the smaller / regional airports - I'd try and get flights on one of those, most people in the UK take this approach.
You generally find that the prices start out low and increase as more people book seats, the moral being it's generally better to book early (note the liberal use of the word "generally".)
Easy jet only goes to / from London Stanstead to Munich in this case (www.easyjet.com - currently shows GBP 83 one way per person inc tax when booked over the net), Ryanair site doesn't list Munich.

Try searching the net for a while, there are also other mainland Europe based airlines to try. Same for Italy to the UK.

You could go via ferry to the mainland and then train to Munich (no idea how long this would take or cost.)

For Germany to Italy why not try the train, at least you will get to see something of the countryside as you blast through it? (I do see that you don't have too much time)

I second Michael, don't take all you money with you as dollars or travellers cheques (search this site for discussions on that), use the ATM's and get yourself a credit card that doesn't charge a separate conversion fee and use that for bigger purchases.

I realise reading this that it isn't going to be too much help - oh well, not everyones an ira and you get what you get when you ask on here!?

Have fun on your trip.

Slightly off topic: teh current edition of U.S. Vogue magazine, in its travel pages, has a little feature on Newcastle. Apparently you'll see some very nice architecture.

BAK

I'll like to add to some of the good advice you already received a suggestion to "bridge" the holidays better so you are not traveling using public transport immediately before or immediately after a holiday. This should also help you with lodging rates & availability.

Where are you arriving/departing from? I noticed some backtracking; I would try to do London somewhere between 12/15-12/23). As far as finances; ATM and two credit cards (one is a backup). Use the local European train and airlines websites. They are excellent to aid on this type of decisions. Good luck!!

Flying from Atlanta to Newcastle. Forgot to mention that bit! And no, I was not planning on having thousands hanging on me at all times...I have an ATM card and will use it for the majority of the time. And, since we are on the money topic, how much money is appropriate? I ask this because if I bring too much I will spend it, and if I bring too little I will be miserable. I know it is hard to say considering you don't know the complete details of the trip (and you don't know me), but for about a month traveling through Europe including lodging, airfare, ground transportation, etc. how much money would be reasonable? Just to be on the safe side...(and to know if I need a raise!)

Thanks to everyone for their help!